Adventure sailing, boat building, and interests of roger mann. Not dedicated to one interest but at the moment adventure sailing is taking a front seat.

Monday, February 13, 2012

XRT specs

Thanks for your comment Wade, here are some answers to your questions.

Length is 24 foot. Hull width at widest point is 22" and below that at the Waterline is 18" which gives it a length to width ratio of 16 which is the same as the inflatable amas. Width when amas extended is 14' and 4' folded. Amas can be lowered 10 inches which reduces the draft when in rivers to 4-5 depending on load. Normal draft at full load of 650 lbs is 7". Weight is 295 lbs. empty and 325 with portage equip. Useful load is 325 lbs.
The struts for the amas are aprox 4-5" above the waterline but they do create spray from waves due to the flat plate area of the sq. support tube going through the hull. I added a plastic airfoil shaped flairing to the front to streamline it and what spay it creates now mostly stays low and trails straight aft. The tubing still creates spray but not a constant soaking. Waves can still break into the boat as well but water drains straight out the Hobie Drive well. The spray is also reduced from tramps that go up to the fwd akas so it is futher reduced. It is a wet boat in rough conditions since water will still make its way through the tramp material.
The reason for the struts is not strength which most folks assume. They are there so that the amas can be positioned where needed and folded quickly. They can swing 3 foot forward or aft and so do not have to be the same, one can be forward and one back. Tramps have to be lowered to do this and can only be used in the netural position but stow quickly by releasing 3 snaps and rolling up. Using straight akas the amas would not rotate so I gave up some drag for what I hope to be a benifit of position and folding. Being able to sweep the amas fwd helps keep the bow from plowing when going downwind and swinging them fwd and aft while on a beam reach is useful to get the ama fwd and weight aft on the windward side. The amas can be folded in aprox. 20 seconds for portage. If they were straight the boat would have to be disassembled for bridges or portage then the breakdown time would have been maybe an hour.
I believe that answers your questions and thanks for the offering of luck in the UFC. Roger